APPENDIX A

Substance (1)	Basic Chemistry	Metallurgy	Extra-Nuclear Physics	Nuclear Physics	Technology (2)
APPENDIX A
TABLE A LIST OF CLASSIFIED SUBSTANCES
Deuterium	Yes	--	Yes	Yes	No
Tritium	Yes	--	Yes	No	No(3)
Beryllium	Yes	Yes	Yes	Yes	No
B¹⁰	--	--	--	Yes	No
Graphite (4)	Yes	--	Yes	No	No
Fission Products	Yes	Yes	Yes	No (5)	No (6)
Polonium (7)	Yes	No	Yes	Yes	No
Thorium	Yes	No	Yes	No (8)	No
*Protactinium	Yes	No	Yes	No (8)	No
Uranium	Yes	No	Yes	No (8)	No
Neptunium	Yes	No	Yes	No (8)	No
Plutonium	Yes	No	Yes (9)	No (8)	No
Elements 95 and above (10)	Yes	No	Yes	No (8)	No
UF₆	Yes	--	Yes	--	No
UCl₄	Yes	--	Yes	--	No
Yes - Declassify; No - Retain Classification at present; -- Not Applicable.
(1) - Classification will be retained on all information on production capacity and stocks available. (2) - This includes description of actual manufacturing operations or reasonable alternates, and laboratory work from which the nature of these operations could be clearly inferred. (3) - Classification will be retained, for the present, on small scale production methods. (4) - This refers only to high purity graphite manufactured specifically for use as a moderator. (5) - The kinetic energies and all nuclear properties of fission products may be declassified (but see 10-181) except: (a) Slow neutron capture cross-sections above 100 barns for radioactive fission products. (b) The absolute fission yield of delayed neutrons. (c) The fission yield of any of the isotopes leading to delayed neutron fission. (6) - This does not prohibit the release of information on the laboratory scale separation of the fission products from one another, but care must be exercised not to reveal information regarding the large scale production of specific radioactive products of fission. (7) - No information is to be disclosed from which the interest of the Project in the use of this substance for classified purposes or its large scale production may be inferred. (8) - Unless permitted by Table B. (9) - No physical or mechanical properties of solid or liquid states of plutonium metal may be declassified. (10) - Information concerning new elements should not be released until approval is received from the Declassification Office.

APPENDIX A
TABLE B NUCLEAR PROPERTIES
SUBSTANCES			All Isotopes listed in box below: (Note restriction on amounts!)	U²³⁶
PROPERTY
Nuclear Properties
	Existence		Yes	No(1)
	Exact Mass		Yes	No
	Spin		Yes	No
	Moment		Yes	No
Methods of Formation of Isotope
	Charged Particle and γ-ray reactions		Yes	No
	Neutron reactions
		Above 25 Mev	Yes	No
		Below 25 Mev	No	No
Reactions Involving Isotopes
	[Including properties (such as existence of the reaction, cross-section and its energy independence, etc.) of reactions, including scattering, fission, etc.]
	Charged particle and γ-ray reactions		Yes	No
	Neutron reactions
		Above 25 Mev	Yes	No
		Below 25 Mev	No	No
Spontaneous Disintegration Properties
	Spontaneous fission		No	No
	Other than spontaneous fission		Yes	No
Energy Levels			Yes(2)	No

LIST OF ISOTOPES TO WHICH FIRST COLUMN APPLIES (Information obtainable only by the use of amounts greater than those in the table below or which otherwise reveals the existence of greater amounts may not be declassified.)
Tracer Quantities	Micrograms	Milligrams	Grams	No Limit(3)
Th²²⁶ , Th²³¹ , Th²³³	Th²²⁷ , Th²²⁹ , Th²³⁴	Th²²⁸	Th²³⁰	Th²³²
Pa²²⁹ , Pa²³⁰ , Pa²³² , Pa²³⁴		Pa²³³	Pa²³¹
U²³⁰ , U²³¹ , U²³⁹	U²³² , U²³⁷	U²³⁴	U²³³ , U²³⁵	U²³⁸
Np²³³ , Np²³⁴ , Np²³⁶	Np²³⁵ , Np²³⁸ , Np²³⁹		Np²³⁷
Pu²³⁴ , Pu²³⁵ , Pu²³⁶ , Pu²³⁷	Pu²³⁸ , Pu²⁴⁰ , Pu²⁴¹		Pu²³⁹
	Cm²⁴⁰ ,Cm²⁴¹ ,Cm²⁴²
Am²³⁸ , Am²³⁹ , Am²⁴⁰ , AM²⁴²	Am²⁴¹

(1) It is permissible to reveal the existence of U²³⁶ as an alpha decay product of Pu²⁴⁰ , but not as a product of any other reaction.
(2) Excepting neutron induced.
(3) But see Table A, Footnote (1).

APPENDIX B

APPENDIX A TO THE 1950 DECLASSIFICATION GUIDE FOR GENERAL APPLICATION AND THE 1950 DECLASSIFICATION GUIDE FOR RESPONSIBLE REVIEWERS

The following information is declassified concerning the nuclear properties of uranium which are of importance in connection with Class I Reactors.

1. Thermal neutron cross sections for uranium

(These are currently accepted values in barns for an approximately Maxwellian neutron spectrum with an average energy corresponding to a neutron velocity of 2200 meters/second.)

Thermal Neutron Cross Section For	U²³⁵	U²³⁸	Natural U
Fission	545	0	3.9
Capture	100	2.6	3.3
Scattering	8.2	8.2	8.2

2. Neutron per thermal neutron fission

v = 2.5 � 0.1 for U²³⁵

3. Fast Fission Effect

The following are typical values of the fast fission contribution to the reactivity of research reactors:

a. In a reactor of the "CP-2" or "GLEEP" type: 2.9%

b. In a reactor of the "CP-3" or "ZEEP" type: 3.1%

4. Resonance Absorption Integral

An approximate empirical formula for the effective value of the resonance absorption integral in natural uranium is:

∫σ^c (E)(dE/E) = 9.25 [1 + 2.67 (S/M)]

Where the value is in barns, the integral is over the range of neutron energy from fission energy to thermal energy, and where S = uranium surface area in cm² and M = uranium mass in grams.

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